1. Field of the Invention
The present disclosure relates to a chamber case of a brake chamber of a vehicle, which allows the brake chamber to have a reduced weight and improved durability.
2. Description of the Related Art
A pneumatic brake system such as an air brake has been used for controlling a medium-sized or large-sized commercial vehicle, particularly a large and heavy vehicle such as a truck or a bus, to run or stop due to its safety and easy operability.
However, in order to control such a large vehicle to run at a high speed, the brake should be operated more sensitively and more rapidly due to the weight of its load, and substantially an air brake having a strong braking force is demanded.
In an air brake system, a most essential part is a brake chamber which makes a stroke of 64 mm with a force of, for example, 1800 kgf by using air pressure.
FIGS. 1 and 2 are cross-sectional views showing an operating state of a general spring-type brake chamber, and the brake chamber includes a spring chamber 11 and a service chamber 12 disposed at upper and lower portions, respectively.
The spring chamber 11 includes a power spring 13 installed therein and generating a force for operating a vehicle brake by an elastic restoring force, a first diaphragm 14 for compressing the power spring 13 by upward deformation caused by an air pressure, a piston 16 installed at an upper surface of the first diaphragm 14 to transmit a compression force to the power spring 13, and a piston rod 17 vertically moving through a hole of a barrier 10 between the spring chamber 11 and the service chamber 12 in an axial direction.
At this time, when the power spring 13 is compressed, the top portion of the power spring 13 is guided by a spring guide 22 installed at an upper inner side of the spring chamber 11, and the bottom portion of the power spring 13 is placed on and supported by a flange portion of the piston 16.
In addition, a first spring 19 is installed between the first diaphragm 14 and the barrier 10, and the first diaphragm 14 is elastically supported by the first spring 19.
Moreover, the service chamber 12 includes a second diaphragm 15 deformed upwards by an air pressure or a force received from the piston rod 17, a push rod 18 connected to the second diaphragm 15 and drawn through a lower through hole of the service chamber 12, and a crevice 21 configured to connect an end of the push rod 18 to a vehicle brake operating mechanism and also operate or release the vehicle brake by a lifting operation of the push rod 18.
At this time, the second spring 20 is installed between a connection plate of the push rod 18 and a bottom portion of the service chamber 12, and the second diaphragm 15 is elastically supported by the second spring 20.
In this configuration, the brake actuator operates as follows.
For example, when the brake is released or a vehicle runs normally, a compressed air is introduced into the spring chamber 11 as shown in FIG. 1.
An edge portion of the first diaphragm 14 is deformed upwards due to the pressure of the compressed air introduced to the spring chamber 11, the power spring 13 is compressed by the air pressure transferred through the piston 16, and the piston rod 17 connected to the first diaphragm 14 is inserted into the spring chamber 11.
Subsequently, as the piston rod 17 moves upwards, the second diaphragm 15 is deformed upwards by the elastic restoring force of the second spring 20, so that the push rod 18 is inserted into the service chamber 12 and the vehicle brake is released by the crevice 21 connected to the push rod 18.
In addition, when the brake is in operation, as shown in FIG. 2, as the air in the spring chamber 11 discharges out, the air pressure applied to the power spring 13 through the first diaphragm 14 and the piston 16 is released, and thus the power spring 13 is expanded by the elastic restoring force.
Subsequently, as the edge portion of the first diaphragm 14 is deformed downwards by the elastic restoring force of the power spring 13, the piston rod 17 is moved downwards, and accordingly the second diaphragm 15 is deformed downwards by receiving, a pressing force from the piston rod 17.
In addition, as the push rod 18 connected to the second diaphragm 15 is drawn from the service chamber 12, the vehicle brake is operated by the crevice 21 connected to the bottom portion of the push rod 18.
Meanwhile, in the general spring chamber, a chamber case surrounding the power spring or the like is made of steel material, and the chamber case made of steel material becomes a factor of increasing the weight of a vehicle.
Therefore, it is demanded to design a chamber case made of lighter material in order to reduce weight of the vehicle.